The Senate's leading voices against in-flight cellphone calls are at it again.

Sens. Lamar Alexander, R-Tenn., and Dianne Feinstein, D-Calif., have sent a letter to Transportation Secretary Anthony Foxx calling for a prohibition on voice calls.

"I'm glad the Department of Transportation is thinking about putting the brakes on a bad idea before it takes flight. Stop and think about what we hear in airport lobbies — babbling about last night's love life, next week's schedule, arguments with spouses — and then imagine hearing the same thing while you're trapped in 17-inch-wide seats thousands of feet above the ground," Alexander said in a statement. "With two million passengers hurtling through the air each day, the Transportation Security Administration would have to hire three times as many air marshals to deal with fistfights."

This isn't Alexander's first commentary on the subject of in-flight phone calls. He weighed in late last year with a similar statement .

Dear Secretary Foxx,
We are writing to express our strong support for a prohibition on the use of mobile wireless services for voice communication on commercial aircraft.
On February 24, 2014, the U.S. Department of Transportation published an Advance Notice of Proposed Rulemaking (Docket No. DOT-OST-2014-0002) regarding the use of mobile wireless devices for voice calls on commercial aircraft. We strongly support the agency’s efforts to preserve the last vestige of quiet in our busy skies. On December 12, we introduced S. 1811, the Commercial Flight Courtesy Act to codify the current prohibition of voice communication use inflight.
Today’s commercial air passengers often must tolerate a challenging flight experience. Constantly changing security measures, smaller seats, and unexpected fees are inconveniences air passengers have come to accept as the new normal. Adding the burden of listening to a cacophony of personal conversations while confined to a 17-inch seat strikes us as unnecessary. We are concerned that the addition of this entirely avoidable aggravation of a confined space will create a possibly hostile atmosphere on commercial flights.
The Department of Transportation’s Federal Aviation Administration (FAA) is responsible for ensuring the safety of the passengers and crew of commercial airlines. Flight crews endure long hours, separation from families, and sometimes difficult passengers. A clear prohibition of phone calls by the FAA, will reduce the likelihood that crew will be forced to place themselves in harm’s way to disrupt physical or verbal altercations between passengers.
Further, it is no secret our skies are being protected by undercover Federal Air Marshalls and we appreciate their service. Were the prohibition on voice communication ended, we are concerned that these agents would be forced to disclose their identity to resolve senseless disputes over inflight phone calls.
We strongly encourage you to finalize a rulemaking to prohibit the use of mobile wireless devices for voice communication inflight. Keeping phone conversations private on commercial flights may not be enshrined in the Constitution, but it is certainly enshrined in common sense. By doing so, we believe you will have the gratitude of the majority of the two million Americans who fly each day.